WO1998029149A1 - Systeme peroperatoire de recuperation de sang et procede afferent - Google Patents

Systeme peroperatoire de recuperation de sang et procede afferent Download PDF

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Publication number
WO1998029149A1
WO1998029149A1 PCT/US1997/024126 US9724126W WO9829149A1 WO 1998029149 A1 WO1998029149 A1 WO 1998029149A1 US 9724126 W US9724126 W US 9724126W WO 9829149 A1 WO9829149 A1 WO 9829149A1
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Prior art keywords
blood
membrane filter
washing fluid
pump
filtrate
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PCT/US1997/024126
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English (en)
Inventor
U. Ramakrishna Shettigar
Original Assignee
Shettigar U Ramakrishna
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Filing date
Publication date
Priority claimed from US08/876,557 external-priority patent/US5876611A/en
Application filed by Shettigar U Ramakrishna filed Critical Shettigar U Ramakrishna
Publication of WO1998029149A1 publication Critical patent/WO1998029149A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/145—Ultrafiltration
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/34—Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
    • A61M1/3403—Regulation parameters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/34—Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
    • A61M1/3403—Regulation parameters
    • A61M1/3406—Physical characteristics of the filtrate, e.g. urea
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
    • A61M1/3621—Extra-corporeal blood circuits
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
    • A61M1/3621—Extra-corporeal blood circuits
    • A61M1/3643—Priming, rinsing before or after use
    • A61M1/3644—Mode of operation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
    • A61M1/3621—Extra-corporeal blood circuits
    • A61M1/3643—Priming, rinsing before or after use
    • A61M1/3644—Mode of operation
    • A61M1/365—Mode of operation through membranes, e.g. by inverted trans-membrane pressure [TMP]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
    • A61M1/3692—Washing or rinsing blood or blood constituents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/147—Microfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/16—Feed pretreatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/22—Controlling or regulating
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/34—Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
    • A61M1/3621—Extra-corporeal blood circuits
    • A61M1/3643—Priming, rinsing before or after use
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
    • A61M1/3621—Extra-corporeal blood circuits
    • A61M1/3669—Electrical impedance measurement of body fluids; transducers specially adapted therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/33—Controlling, regulating or measuring
    • A61M2205/3306—Optical measuring means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/33—Controlling, regulating or measuring
    • A61M2205/3331—Pressure; Flow
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/33—Controlling, regulating or measuring
    • A61M2205/3331—Pressure; Flow
    • A61M2205/3334—Measuring or controlling the flow rate
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/33—Controlling, regulating or measuring
    • A61M2205/3368—Temperature
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/33—Controlling, regulating or measuring
    • A61M2205/3375—Acoustical, e.g. ultrasonic, measuring means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/75—General characteristics of the apparatus with filters
    • A61M2205/7554—General characteristics of the apparatus with filters with means for unclogging or regenerating filters

Definitions

  • the present invention relates to methods and apparatus for recovery, purification and reinfusion of blood lost at a wound site during surgery. More specifically, the present invention relates to aspiration of shed blood from a wound site during intraoperative surgery, on-line purification of aspirated blood by filtration and cell-washing using filtration membranes, and reinfusion of purified autologous blood to the patient on a real-time basis.
  • Blood lost during intraoperative or post-surgical recovery periods can be collected in a container and reinfused to the patient provided the salvaged blood is free of impurities.
  • Typical impurities are blood clots, tissue debris, hair, foreign particles, activated coagulation factors, denatured proteins, plasma-free hemoglobin, and any other fluids (e.g. , irrigation fluid) that are being added into the wound site by medical personnel.
  • suction is provided to remove the shed blood, other accumulated fluids, blood clots and tissue debris. Impurities in the salvaged blood are generally filtered using a 40 micron filter to remove particles greater than 40 microns in size.
  • the blood is then subjected to "cell- washing" .
  • the cell washing technique may involve mixing blood with a physiological solution (e.g. , saline or Ringer's Solution) in equal proportion to the blood, and then centrifuging the diluted blood to recover the heavier blood cells, which are suitable for reinfusion to the patient.
  • a physiological solution e.g. , saline or Ringer's Solution
  • each is composed of three units— namely, an aspirator unit, a cell washing unit and a blood reinfusion unit.
  • the typical aspirator unit consists of a suction handle attached to suction tubing, which is connected to an emboli filter reservoir.
  • the emboli filter is generally provided with an air vent line, a degassifier, a 40 micron filter and a blood reservoir. Controlled suction is usually applied with a vacuum source via the vent line of the emboli filter. The vacuum aspirates shed blood, along with other impurities, from the wound site into the filter reservoir. Impurities larger than 40 micron size will be trapped in the emboli filter.
  • Filtered blood is usually pumped to a cell centrifuge machine where it is mixed with an appropriate "washing fluid” and centrifuged for a specified time until the heavier blood cells are separated from the plasma.
  • This method is cumbersome, time consuming and requires an operator to attend the system continuously.
  • an on-line apparatus for providing continuous processing of autologous blood, which would minimize loss of precious blood elements and which would reinfuse to the patient his/her own blood on a real-time basis. It would be a further advancement to provide an automatic system which would reinfuse whole blood at a specified hematocrit level free of air emboli.
  • an intraoperative blood salvaging and purification system removes blood from a wound or surgical site, filters and purifies the blood by the addition thereto of washing fluid at a rate determined by a selected hematocrit level detected in the blood, and returns the blood to the patient on a substantially continuous basis.
  • the intraoperative blood salvaging and purification system is structured to process large amounts of blood and to return the salvaged blood to the patient free of impurities larger than a selected molecular size, and free of emboli.
  • the filtration system of the present invention maintains filtration integrity by providing reverse filtration to flush out clogging impurities from the filtration membrane.
  • the intraoperative blood salvaging system generally comprises a means for removing blood from a wound site or from an operative or post-operative site and means for mixing the blood with a washing fluid prior to delivering the blood to an emboli filter for initial washing of the blood.
  • the system also includes means for further filtering the salvaged blood to remove impurities larger than a selected molecular size through use of a membrane filter having a selected maximum pore size.
  • the blood salvaging system further includes structural means for delivering filtered and purified blood back to the patient on a substantially continuous basis, free of emboli.
  • a cardiotomy filter and reservoir are positioned to receive aspirated blood from the wound site and serve to (i) de-aerate the aspirated blood under vacuum; (ii) remove particle emboli, blood clots and other matter larger than a selected micron size; (iii) provide a reservoir large enough to accommodate large volumes of aspirated blood and washing fluid, and maintain a continuous source of liquid for the membrane filter and reinfusion line, thereby eliminating air from entering the membrane filter and reinfusion line; and (iv) monitor the extent of dilution of the aspirated blood (i.e. , washing/blood ratio) by the washing fluid.
  • the cardiotomy reservoir is provided with (i) an emboli filter having about a 40 micron pore size; (ii) a reservoir having a capacity of about 4 to 5 liters; (iii) a hematocrit sensor (also referred to hereafter as "HCT-1") positioned at the lower end of the reservoir at a point thereof corresponding to a capacity of about 50 ml to 200 ml; (iv) a liquid overflow sensor which detects when liquid reaches the top end of the reservoir and generates an alarm signal if an overflow condition is imminent; and (v) a liquid level sensor positioned in connection with the reservoir in a location corresponding to a reservoir capacity of about 50 ml to 200 ml.
  • HCT-1 hematocrit sensor
  • the hematocrit sensor, HCT-1 may preferably serve as the most reliable liquid level sensor. While ultrasonic level sensors have been used in the past as level sensors, they may occasionally fail due to air entrapment between the sensor and the reservoir wall.
  • the cardiotomy filter is usually operated under a maximum vacuum pressure of -120 mm Hg to remove or aspirate blood from the wound site. Aspirated blood must be mixed with a washing fluid in order to remove impurities present in the blood. The efficiency of removal of impurities is proportional to the volume of washing fluid used for cell washing. In conventional methods, blood and washing fluid are mixed in equal proportion. While bleeding in the wound site varies with time, ranging from O to 3,000 ml/min. , the actual bleeding rate at any given moment is not known.
  • the present invention presents a novel method of providing the optimal amount of washing fluid proportional to the amount of blood being aspirated by measuring the hematocrit (HCT-1) of the aspirated blood, pre-mixed with washing fluid, which is collected in the cardiotomy reservoir.
  • the hematocrit value of a given sample of blood corresponds to the amount of blood cellular debris contained in the blood.
  • washing fluid is delivered for mixture with the aspirated blood. If the measured hematocrit value is greater than the pre-set value, then washing fluid is delivered at a pre-set maximum flow rate for mixture with aspirated blood until the measured hematocrit value (HCT-1) decreases below the pre-set value. Washing fluid delivery stops irrespective of the measured hematocrit value HCT-1 when there is a detected overflow in the cardiotomy reservoir as monitored by an overflow level sensor.
  • the present invention provides a continuous on-line method of removing impurities from blood which are greater than a specified molecular size and reinfusing the purified blood to the patient at a specified hematocrit value, free of air emboli.
  • This is achieved by pumping the filtered blood from the emboli filter reservoir through a membrane ultrafilter or a plasma filter under a positive pressure while the fluid portion (i.e. , a percentage of the non-cellular volume) of the filtered blood is continuously measured using a second on-line hematocrit monitor (HCT-2) located at the blood outlet of the membrane filter.
  • An ultrafilter may be used for membrane filtration and may preferably have a pore size ranging from 40,000 daltons to 400,000 daltons molecular weight cut off.
  • a membrane with a pore size cut off of 100,000 daltons It may be most suitable to use a membrane with a pore size cut off of 100,000 daltons. However, if larger size impurities are to be removed, then a pore size of 400,000 daltons or even a plasma filter having a pore size of 0.4 micron may be used.
  • Suitable membrane filters such as ultrafilters or plasma filters, are structured with a blood side (i.e. , comprising one or more pathways for blood movement) and a filtrate side (i.e. , comprising a fluid waste product pathway).
  • the blood side and filtrate side are separated by one or more porous membranes having a selected porosity as previously described.
  • a blood exit port is in fluid communication with the blood side to direct filtered and purified blood from the membrane filter for reinfusion.
  • a filtrate outlet is in fluid communication with the filtrate side of the membrane filter to remove and dispose of the filtrate.
  • the membrane filtration rate (i.e., the rate at which waste fluid is removed from the blood) is regulated by a filtrate pump the speed of which is set to provide a flow rate which is inversely proportional to the measured hematocrit HCT-2.
  • the maximum speed at which the filtrate pump may operate is dictated by the operating characteristics or specifications of the membrane filter.
  • the filtrate pump speed is gradually decreased until the HCT-2 value approaches or equals the set point.
  • the fraction of cellular volume, or hematocrit, in the blood being processed through the apparatus is monitored continuously by measuring the impedance of the blood at a specified frequency using two stainless steel electrodes positioned near the outlet of the membrane filter or plasma filter.
  • the electrodes supply a current of ten micro amperes at a frequency of five thousand Hertz.
  • Measured conductivity of blood is known to be proportional to the fraction of noncellular fluid volume in the blood.
  • filtered blood is not continuously recirculated to the emboli filter during membrane filtration as is the case in prior devices. Rather, the filtered blood, during membrane filtration, is continuously directed from the membrane filter to a blood collection bag for reinfusion to the patient in single pass.
  • negative pressure exists on the filtrate side of the membrane filter.
  • the negative pressure on the filtrate side may decrease below a permissible level (e.g. , -50 mm Hg, as determined by the specifications of the membrane filter) due to the gradual deposition of protein and cellular particles on the blood side of the membrane filter.
  • a permissible level e.g. , -50 mm Hg, as determined by the specifications of the membrane filter
  • filtration of blood is stopped and reverse filtration is conducted for a selected time period (e.g. , one minute).
  • a selected time period e.g. , one minute.
  • washing fluid from a washing fluid bag is pumped through the filtrate side of the membrane filter, causing reverse filtration across the membrane.
  • Reverse filtration clears the solid deposits from the membrane pores and the resulting fluid is reintroduced to the cardiotomy filter via the suction line so as to remove any particulates, blood clots and air emboli from the reverse-filtered fluid.
  • the reverse-filtered fluid is collected in the cardiotomy reservoir to be purified further by the membrane filter in the next cycle of membrane filtration.
  • reverse filtration using washing fluid is continued for the pre-set period (for example, 1 minute), and then membrane filtration of the diluted blood is resumed.
  • high positive pressure may occur on the blood side of the membrane filter as indicated by a pressure sensor connected thereto.
  • This high pressure (e.g., 150 mm Hg) may be due to (i) excessively high blood flow rate, (ii) excessively high hematocrit, (iii) clogging or clotting in the blood lumen of the membrane filter, or (iv) blockage in the blood reinfusion line.
  • High pressure is relieved respectively by (i) decreasing the blood pump speed, (ii) decreasing the filtrate pump speed, (iii) reverse filtration of the membrane filter using the washing fluid, (iv) checking for any blockage in the blood infusion line, and/or v) heparinization of blood and washing fluid.
  • a single tube clamp with four operative channels is provided to accommodate at least four tubes of the apparatus.
  • the single clamp operates to selectively open certain tubings or fluid lines while occluding others to effect a switch from membrane filtration to reverse filtration automatically.
  • membrane filtration occurs by allowing the purified blood to flow into a blood collection bag, by allowing the washing fluid to flow directly into the suction line of the cardiotomy filter reservoir and by regulating the filtrate pump speed.
  • both the blood and filtrate pumps stop, the washing fluid is directed to the filtrate port of the membrane filter instead of to the suction line, and the blood outlet line of the membrane filter is directed to the suction line of the cardiotomy filter reservoir instead of to the blood collection bag.
  • the washing fluid flushes out the contents of the blood side of the membrane filter by flowing across the membrane from the filtrate side to the blood side, and then it flows into the cardiotomy reservoir after being filtered by the cardiotomy emboli filter. A rise in the liquid level in the cardiotomy reservoir results.
  • the HCT-1 sensor detects liquid (not air) which signals reverse filtration to stop and membrane filtration to start.
  • the reliability and simplicity of the system is improved by the use of the single clamp instead of two or four clamps to switch from membrane filtration to reverse filtration.
  • the purified (washed) blood leaving the blood exit port of the membrane filter flows into a blood collection bag, which is hung from an i.v. pole.
  • the height of the blood collection bag above the membrane filter, and the speed of the blood pump, determines the positive pressure required for membrane filtration.
  • the height of the blood collection bag may be adjusted such that the positive pressure (as indicated by a pressure sensor located at the inlet port of the membrane filter) does not exceed a maximum permissible pressure (for example, 150 mm Hg).
  • a programmable control unit is connected to the blood salvaging system of the present invention and is in electrical communication with many elements of the system, including all of the hematocrit sensors, the overflow sensor, all of the pressure sensors, all of the pumps, the multi-channel clamp and a clamp associated with the blood reinfusion line.
  • the control unit is programmed to emit an alarm responsive to certain perceived conditions, such as a dangerous increase in pressure, so that an operator of the system (i.e. , surgical personnel) can monitor the operation of the system as may be necessary.
  • the control unit includes programming which determines, for example, when the pumps and clamps should be activated or deactivated responsive to a given condition detected by the various sensors.
  • the present invention is structured to provide a most reliable and efficient intraoperative autotransfusion system which can operate on-line continuously on a real-time basis in order to collect, purify and reinfuse to a patient his/her own shed blood.
  • FIG. 1A is a schematic diagram illustrating the intraoperative autotransfusion system of the present invention operating in the membrane filtration mode
  • FIG. IB is a schematic diagram illustrating the intraoperative autotransfusion system shown in FIG. 1A operating in the reverse filtration mode
  • FIG. 2 is a schematic diagram illustrating the function and control logic of the hematocrit sensor (HCT-1 ) located at the lower end of the cardiotomy reservoir;
  • FIG. 3 is a schematic diagram illustrating the function and control logic of the positive pressure sensor (PI) located at the membrane filter blood inlet;
  • FIG. 4 is a schematic diagram illustrating the function and control logic of the negative pressure sensor (P2) located at the membrane filter filtrate outlet;
  • FIG. 5 is a schematic diagram illustrating the function and control logic of the hematocrit sensor (HCT-2) located at the blood exit port of the membrane filter;
  • FIG. 6 is a schematic diagram illustrating the function and control logic of the overflow sensor located at the top end of the cardiotomy reservoir
  • FIG. 7 is a representational cross section view of the pneumatically driven tubing clamp; and FIG. 8 is a perspective view of a representational model of the control unit connected to the structural elements of the blood salvaging apparatus.
  • FIGS. 1A, IB, 7 and 8 The structural elements of the blood salvaging apparatus of the present invention are shown in FIGS. 1A, IB, 7 and 8.
  • a programmable control unit is associated with the structural elements of the apparatus.
  • the control unit designated CU in the drawings, is in electrical communication with several of the structural elements of the apparatus to monitor and regulate the operation of the apparatus as a whole, as explained more fully hereinafter. However, such electrical connections are not shown in the drawings form the sake of clarity.
  • Some of the programmed functions provided by the control unit CU are also illustrated in FIGS. 2-6.
  • the control unit CU is turned on and all timing clocks and alarms are set at zero or are reset.
  • certain values and times may be set at a default value or time.
  • some of the values or times may be input by the operator, including, for example, a washing fluid/blood dilution ratio, the length of time for conducting reverse filtration and the speed of the blood pump to coordinate with the anticipated length of the surgical procedure.
  • the suction means 12 generally includes a conventional handle and a suction tip (not shown in detail).
  • the suction means 12 is connected to a length of suction tubing 14, the other end of which is connected to the blood inlet port 16 of an emboli filter 18, otherwise called a cardiotomy filter, via a Y-connector 15.
  • the emboli filter 18 may generally consist of a polyurethane sponge coated with an antifoam silicone compound which assists in the degassification of the aspirated blood.
  • the polyurethane sponge may be enclosed by a filter fabric having a pore size of about 40 microns to assure removal from the blood of particles larger than 40 microns in size.
  • the emboli filter 18 is enclosed in a structural casing 20 which provides a large reservoir 20.
  • the reservoir 20 is provided with a vent line 22 at its top end and a blood outlet port 24 at its bottom end.
  • the vent line 22 is connected to a vacuum line which may be connected to a controlled vacuum source 28 via an air filter 30.
  • Most operating rooms are generally equipped with a vacuum source which can be controlled at any desired value.
  • washing fluid is mixed with the aspirated blood at a rate proportional to the detected hematocrit of the blood collected in the reservoir 20.
  • a hematocrit sensor 32 (HCT-1) is connected to the wall of the reservoir 20 at a level thereof corresponding to about a 100 ml to 200 ml capacity of the reservoir 20.
  • a minimum volume of liquid (100 ml to 200 ml) must always be maintained in the reservoir 20 as a liquid seal to prevent air being drawn into the system.
  • the HCT-1 hematocrit sensor 32 monitors both the air-liquid interface and the hematocrit of the liquid.
  • both a hematocrit sensor and a separate sensor for detecting the air-liquid interface may be used.
  • An overflow sensor 34 which may preferably comprise another hematocrit sensor, is connected to wall of the reservoir 20 at a level thereof corresponding to about a 4 to 5 liter capacity of the reservoir 20. The overflow sensor 34 detects the liquid/air interface of the fluid in the reservoir 20 at that level and initiates an alarm if liquid overflow in the reservoir 20 is imminent.
  • a pre-set value is determined for detecting by the HCT-1 sensor 32, and that -livable is stored in the control unit (FIG. 8).
  • the pre-set value of HCT-1 is dependent on the washing fluid/blood dilution ratio and on an assumed hematocrit level of the blood as it is shed from the wound or surgical site.
  • the resulting hematocrit value that should be detected by the HCT-1 sensor 32 is 11.7%. If, for example, the washing fluid/blood dilution ratio is set by the operator to be 1.5, then the pre-set hematocrit value would be higher than 11.7%.
  • washing fluid 36 is pumped rapidly (e.g. , 332 ml/min) by a washing fluid pump 38 towards the suction line 14 from a retainer bag 40.
  • the washing fluid travels through a washing fluid conduit 44 connected to a Y-connector 46 and through a first washing fluid conduit 48 which is engaged by a tubing clamp 50.
  • the washing fluid 36 which may preferably contain heparin, is mixed with aspirated blood at the Y-connector 15 and the admixture flows into the emboli filter 18 where it collects in the reservoir 20.
  • the washing fluid pump 38 remains on until the hematocrit detected by the HCT-1 sensor 32 falls below the pre-set value (e.g. , less than 11.7%).
  • the blood pump 52 When the diluted blood volume in the reservoir 20 is above the minimum volume of 100 ml to 200 ml, as detected by the hematocrit HCT-1 sensor 32, then the blood pump 52 operates to draw diluted blood from the reservoir 20.
  • the diluted blood moves through the exit port 24, to the membrane filter 54 via a Y-connector 56 and through the blood inlet port 58 of the membrane filter 54.
  • the membrane filter 54 may be a conventional membrane separator with a pore size ranging from 40,000 daltons to 400,000 daltons molecular weight cut off. It may be preferable to use a membrane with a pore size cut off of 100,000 daltons.
  • a pore size of 400,000 daltons, or even a plasma filter having a pore size of 0.4 micron may be used.
  • the membrane filter is generally structured with a blood pathway (or several blood pathways, such as a plurality of tubules) and a filtrate pathway.
  • the blood and filtrate pathways are separated by one or more membranes of selected porosity as described above.
  • Filtration is induced by a controlled transmembrane pressure differential which is monitored by two pressure sensors 62 and 64.
  • Positive pressure, PI at the blood inlet port 58 is measured by a positive pressure sensor 62 which is connected to the Y-connecter 56 via an air pressure chamber 66 and an air filter 68.
  • the air chamber 66 and air filter 68 are required to maintain sterility in the blood lines and also to keep the blood from contacting the pressure sensor 62, thereby enabling the sensor to function reliably.
  • a vent line 69 with a tubing clamp 70 is connected to the air chamber 66 to provide pressure relief if necessary.
  • An audible alarm device such as may be located in the control unit (FIG.
  • Negative pressure, P2 on the filtrate side 61 of the membrane filter 54 is measured by a negative pressure sensor 64 which is connected to the filtrate side port 72 via an air filter 74.
  • Negative pressure P2 on the filtrate side 61 is induced by the filtrate pump 76, which draws filtrate from the membrane filter 54 through the filtrate outlet 78 via a Y-connector 80 and a filtrate line 82.
  • the filtrate pump 76 pumps the filtrate 86, in the direction of arrows 87, into a collapsible waste bag 84 where the filtrate (waste) 86 is collected.
  • the speed of the filtrate pump 76 is regulated by a third hematocrit sensor 88
  • HCT-2 located near the blood exit port 90 of the membrane filter 54.
  • a pre-set value e.g. , 30%
  • the filtrate pump 76 speed increases to maximize filtration and reaches a maximum permissible value (e.g., 332 ml/min), as determined by the manufacturer's specifications for the pump and the membrane filter.
  • the pre-set value for the HCT-2 sensor 88 is that hematocrit value of the blood which is most appropriate for the patient. In other words, it is generally considered that a 30% hematocrit level is appropriate for reinfused blood, but the hematocrit level of the blood may normally range from 20% to 40%.
  • the HCT-2 sensor 88 may be set (FIG. 8) to detect any hematocrit value in that range.
  • the maximum permissible filtration rate is determined by the manufacturer's specifications for the membrane filter (e.g. , in terms of the pressure values that may be maintained in the membrane filter).
  • the blood pump 52 is off, but the speed of the blood pump 52 is increased gradually over time until it reaches a selected maximum speed, for example, 500 ml/min.
  • the maximum speed is determined by the manufacturer's specifications for the pump and by the selected dilution ratio of washing fluid to blood.
  • the blood pump 52 speed is set by the control unit CU (FIG.
  • the hematocrit (cellular volume fraction) of blood is measured continuously by measuring the conductivity of the blood at a specified frequency using two stainless steel electrodes 89 positioned in proximity to the blood exit port 90 of the membrane filter 54.
  • Such conductivity monitors are readily available on the market (Sesammlungc, Chemin des Muriers, Irigny, France).
  • the electrodes 89 supply to the blood a current of ten microamperes at a frequency of five thousand Hertz. Measured conductivity of blood is known to be proportional to its noncellular volume fraction.
  • clamp 50 is shown in FIG. 1A and FIG. IB as if it were two separate clamps for the sake of clarity. However, there is, in fact, only one clamp 50 (see FIG. 8) which is structured to engage and alternatively clamp four different tubing lines, namely washing fluid lines 48 and 106 and blood circulation lines 96 and 104. The structure and operation of the clamp 50 is described more fully hereinafter.
  • washing fluid line 48 and blood circulation line 96 are open and washing fluid line 106 and blood line 104 are occluded in a closed position by the clamp 50.
  • the blood collection bag 92 may be hung from an i.v. pole above the membrane filter 54.
  • the blood collection bag 92 serves as a reservoir for the washed and filtered blood to be reinfused to the patient. It also serves to provide a positive pressure condition for membrane filtration and for blood reinfusion to the patient by virtue of its positioning above the membrane filter and above the level of the patient.
  • the venous filter 94 removes any blood clots from the blood prior to its reinfusion and also serves to trap any air emboli.
  • An ultrasonic air detector 102 mounted to the venous filter chamber 94 detects entrapment of any air emboli in the venous filter chamber 94.
  • the venous valve 97 is structured to remain in a closed position when no power is applied to the system. That is, it requires the application of electricity to keep the venous valve 97 open so that blood may be reinfused to the patient. In the event of a power failure, however, the venous valve 97 will automatically close, preventing reinfusion. Further, the venous valve 97 will remain open as long as no air emboli are detected in the venous filter 94 as monitored by an ultrasonic air detector 102. When the air detector 102 detects air emboli, the venous clamp 97 closes and activates an audio/ visual alarm (e.g., "Air in the Venous Line"). Once the alarm is activated, it may be cancelled only by the operator, and the venous valve 97 may be reopened only after venting out any trapped air via the vent line 108 attached to the venous filter chamber 94.
  • an audio/ visual alarm e.g., "Air in the Venous Line”
  • the blood salvaging system automatically switches from membrane filtration (i.e. , blood washing) to reverse filtration whenever one of three conditions occur, as described below:
  • reverse filtration is initiated and controlled by the activation of a single clamp 50, which has four tubing channels to accommodate tubing lines 96, 104, 48 and 106.
  • the first two channels of the single clamp 50 retain blood lines 96 and 104 which both connect to the Y-connector 91 in fluid communication with the hematocrit HCT-2 sensor 88 located in proximity to the blood exit port 90 of the membrane filter 54.
  • line 104 remains clamped in a closed position and line 96 remains open, as shown in FIG. 1A.
  • the non-activated condition of the clamp 50 is represented by the left-facing arrow of the clamp 50.
  • FIG. IB describes the blood salvaging system of the present invention in the reverse filtration mode.
  • FIG. IB The structural elements shown in FIG. IB are the same as those in FIG. 1A, except that clamp 50 is activated, as suggested by the right-facing arrow associated with the clamp 50 shown and the blood pump 52 and filtrate pump 76 are off.
  • both the blood pump 52 and the filtrate pump 76 stop, but the washing fluid pump 38 remains on.
  • the clamp 50 moves upon activation to permit the flow of washing fluid 36 from the fluid retainer bag 40 to the filtrate outlet 78 of the membrane filter 54 via line 44, through the Y-connector 46, through line 106 and through the Y-connector 80 to the filtrate outlet 78. Washing fluid line 48 remains closed.
  • the washing fluid pumped to the filtrate outlet 78 flows through the membrane pores from the filtrate side 61 to the blood side 60 of the membrane filter 54. During this procedure, the membrane pores are cleared of any cellular or particle deposits.
  • the resulting washing fluid in which is suspended cellular and particle deposits dislodged from the membrane pores, leaves the blood exit port 90 and flows to the inlet port 16 of the emboli filter 18 via the Y-connector 91, blood line 104 and Y-connectors 42 and 15. Blood line 96 remains closed during this time.
  • FIG. 2 schematically illustrates the control logic defining the interaction between the hematocrit HCT-1 sensor 32, the washing fluid pump 38, blood pump 52, filtrate pump and the clamp 50, all of which are controlled by the control unit (FIG. 8).
  • An amount of washing fluid is circulated through the system to prime the system and to remove any air bubbles.
  • the hematocrit HCT-1 sensor 32 monitors 202 both the hematocrit and the liquid-air interface in the reservoir 20. If the measured hematocrit value is less than zero 204, the HCT-1 sensor 32 has detected air instead of liquid; that is, the liquid level in the reservoir 20 is below the pre-set minimum limit.
  • the system automatically switches over to the standby mode 206 for a pre-set time period 208 (e.g., one minute).
  • a pre-set time period 208 e.g., one minute.
  • the washing fluid pump 38, blood pump 52 and filtrate pump 76 are stopped 206 and the clock is initialized and set to begin the selected time period "t. "
  • a further drop in the level of liquid in the reservoir 20, below the pre-set minimum limit, is prevented by the stoppage of both the blood pump 52 and the filtrate pump 76.
  • the washing fluid pump 38 need not be stopped during the standby mode, but stoppage of the washing fluid pump 38 during standby preserves washing fluid which may otherwise be used for filtration.
  • the period of the standby mode may be pre-set by the operator to any desired length of time at initiation of the system (FIG. 8).
  • the HCT-1 sensor 32 continues to monitor the liquid/air interface during the standby mode 209. Blood may be aspirated into the reservoir 20 during the standby mode, thereby increasing the level of liquid in the reservoir 20 above the pre-set minimum limit. If the liquid level in the reservoir 20 rises above the pre-set minimum level during the standby period (i.e. , HCT-1 > 0) 210, the standby mode is cancelled and membrane filtration re-commences 212. However, if no blood is aspirated during standby, the level of liquid in the reservoir 20 may remain constant or may drop even further below the minimum limit. If there is no detected increase in the fluid level (i.e. , no interruption of the standby mode) at the end of the standby period 214 (i.e.
  • the system automatically switches to reverse filtration 216 which raises the liquid level above the pre-set minimum level by the introduction of washing fluid and blood from the membrane filter 54 into the reservoir 20.
  • the period of reverse filtration may be pre-set by the operator at the initiation of the system (FIG. 8). In FIG. 2, the pre-set period is shown as one minute.
  • the clamp 50 is activated, and both the blood pump 52 and filtrate pump 76 remain off while the washing fluid pump 38 remains on at a low speed.
  • the resulting mixture of washing fluid and blood leaving the blood exit port 90 and entering the emboli filter 18 via line 104 accumulate in the reservoir 20, which leads to a rise in the level of liquid above the minimum limit.
  • the hematocrit is remeasured 202.
  • the HCT-1 sensor 32 should detect liquid 210.
  • the clamp 50 returns to the inactive mode and membrane filtration begins again 212.
  • the speed of the blood pump 52 increases gradually and the filtrate pump 76 is re-started.
  • the hematocrit level of the blood in the reservoir 20 is determined by the HCT-1 sensor 32, at 224. If the hematocrit level is above the pre-set hematocrit value 225, the washing fluid pump 38 is started 226 and will remain on as long as the measured hematocrit HCT-1 remains above the pre-set hematocrit value (e.g. , 11.7%) 202.
  • the washing fluid pump 38 stops or remains off 228, thereby preventing excess dilution of aspirated blood.
  • the invention automatically regulates the washing/blood ratio at a desired value and maintains a liquid seal in the reservoir 20 such that a mixture of washing fluid and blood is circulated in the system during the entire period of the surgical procedure irrespective of whether bleeding and aspiration, are occurring at any given time.
  • FIG. 3 schematically illustrates the control logic of the pressure sensor 62 and its interactions with the clamp 50, the washing fluid pump 38, the blood pump 52 and the filtrate pump 76.
  • the pressure sensor 62 measures the positive pressure, PI, at the blood inlet port 58 of the membrane filter 54.
  • PI may rise due to (i) an increase in blood flow rate, (ii) an increase in the hematocrit of circulating blood, (iii) a blockage in the reinfusion line 98, or (iv) a blockage in the blood side 60 of the membrane filter 54 by blood clots, which may be caused by insufficient heparinization.
  • a PI value greater than a selected maximum pressure may damage the membrane filter 54 and also damage the blood cells travelling through the membrane filter 54, causing hemolysis.
  • the maximum limit of the pressure PI is specified by the manufacturers of membrane filters.
  • an upper limit value for PI is shown to be 150 mm Hg, reflecting a pressure value above which a dangerously high pressure condition may be reached. Therefore, 150 mm Hg represents a safe upper limit.
  • membrane filtration starts and the speed of the blood pump 52 increases gradually from zero. The alarm is also reset. Measurement of positive pressure begins 302. As long as PI is not greater than 150 mm Hg 303, the blood pump 52 will gradually increase in speed until the blood pump 52 reaches a selected maximum speed (e.g. , 500 ml/min.) It should be noted that at initiation of the apparatus, the surgical personnel may program into the control unit (FIG. 8) the desired maximum speed of the blood pump 52 in accordance with the manufacturer's specifications for the particular membrane filter. It is preferable to operate the system at as high a blood flow rate (i.e. , 500 ml/min.) as possible since blood processing rates (i.e.
  • the rate at which purified blood is reinfused to the patient increases with the increase in blood flow rate.
  • increased amounts of protein and blood cell adhesion occur on the blood side 60 of the membrane filter 54, which may partially clog the membrane and lead to higher PI values, despite a reduction in blood flow rate to as low as 250 ml/min. (i.e. , corresponding to 50% of the maximum blood flow rate).
  • the blood processing rate, or the rate at which the purified blood is reinfused to the patient also decreases. Therefore, the system should operate as close to the maximum blood pump speed as possible while staying within a safe PI value.
  • an alarm will sound 306 (FIG. 8) notifying the operator of the condition.
  • the control unit CU initially attempts to lower PI by decreasing the blood pump speed gradually. Therefore, as long as the blood pump speed remains above an average flow rate of 250 ml/min. 307, the blood pump speed will gradually be decreased 308 in an attempt to lower the PI value. When, after gradually decreasing the blood pump speed, it becomes necessary to reduce the blood flow rate (i.e. , pump speed) below 250 ml/min.
  • the control unit CU determines if the blood pump 52 is still operating at a rate greater than a minimum level below which blood purification and reinfusion cannot take place (e.g. , 100 ml/min) 310. If the blood pump speed is still greater than the minimum speed 311, the control unit CU stops membrane filtration and goes into reverse filtration mode 312 for a pre-set period of time, t. The membrane should be cleared of clots and debris during the reverse filtration process. Following the time period for reverse filtration (i.e., t + ⁇ t), membrane filtration is re-commenced by the control unit CU, 300.
  • a minimum level below which blood purification and reinfusion cannot take place e.g. , 100 ml/min
  • the operator is called for assistance 318. The operator may then check for any blockage in the reinfusion line 98, the venous catheter 100, the venous valve 97 and/or the venous filter 94.
  • FIG. 4 schematically illustrates the control logic and interaction of the negative pressure sensor 64 with the clamp 50, the washing fluid pump 38, the blood pump 52 and the filtrate pump 76.
  • a maximum limit for the negative pressures which may be sustained on the filtrate side 61 of the membrane filter 54 is set by the filter manufacturers and is determined by the degree of damage to which the blood cells and membrane filter may be subjected at high negative pressures.
  • the maximum safe negative pressure of a membrane filter varies with the membrane characteristics and method of assembly of each kind and make of membrane filter. Normally, membrane filtration proceeds within the safe limits of negative pressure P2 on the filtrate side 61.
  • the membrane pores may become clogged with protein and cellular deposits. In time, such deposits may grow to form a gel on the membrane surface, which, in turn, may impose additional resistance to proper filtration. This gel formation may increase the negative pressure necessary to obtain the desired filtration rate.
  • Negative pressure P2 is measured at the filtrate port 72 by pressure sensor 64, as indicated in FIG. 4 at 400.
  • the system automatically switches from filtration to reverse filtration 404 for a pre-set period of time, t.
  • the clamp 50 is activated thereby closing off the blood line 96 and washing fluid line 48, the blood pump 52 and filtrate pump 76 stop and the washing fluid pump 38 is operated at a slow speed.
  • FIG. 4 suggests that the period of reverse filtration may be one minute, however the time period may be selected to any desired value by the operator.
  • the system returns to membrane filtration 408 automatically.
  • the clamp 50 is deactivated thereby opening blood line 96 and washing fluid line 48, the speed of the blood pump 52 gradually increases, and the filtrate pump 76 begins to operate.
  • FIG. 5 shows the operating logic of the hematocrit HCT-2 sensor 88 located at the blood exit port 90 of the membrane filter 54, and its interaction with the filtrate pump 76.
  • the hematocrit HCT-2 of the washed and filtered blood that is to be reinfused to the patient is controlled at a selected value by regulating the filtration rate through the membrane filter 54.
  • the desired value of the hematocrit HCT-2 may be selected by the operator 500, and is shown in FIG. 5, for example, to be 30% .
  • the hematocrit HCT-2 level is constantly measured 502. When the measured HCT-2 value drops below the selected value 504, the filtration rate is increased automatically by increasing the filtrate pump speed 506.
  • the filtrate pump speed is decreased 512 to bring the HCT-2 value back into range.
  • the HCT-2 value exceeds the upper limit, e.g. , above 40%) 514, then the filtrate pump is stopped 516 until such time as the HCT-2 value is near 30% .
  • an HCT-2 value above 50% may cause hemolysis in the membrane filter 54 and may lead to excessive pressure at PI. It may be appreciated that for the above reasons, the blood salvaging system of the present invention automatically acts to prevent excessive HCT-2 values at the blood exit port 90.
  • FIG. 6 describes the operating logic of the overflow liquid sensor 34 and its interaction with the washing fluid pump 38, the blood pump 52 and the filtrate pump 76.
  • Liquid in the reservoir 20 may overflow due to the addition of too much washing fluid by the washing fluid pump and/or due to high amounts of blood being aspirated as a result of excessive bleeding in the wound site.
  • the overflow of liquid in the reservoir 20 is sensed by an air-liquid sensor 34, which may be an ultrasonic sensor or photoelectric sensor.
  • a hematocrit sensor 34 connected to the wall of the reservoir 20 near the top end thereof is used to detect the air-liquid interface, indicated at 600 in FIG. 6.
  • the overflow sensor detects air 602
  • the resulting measured hematocrit value becomes a negative value.
  • the sensor 34 detects liquid 604, it measures either a zero or a positive value.
  • An overflow alarm is activated 606 and the control unit CU determines if the washing fluid pump is on or off 608. If the washing fluid pump is on 610, it is stopped 612 to prevent any further dilution of the aspirated blood in the reservoir 20. If the control unit CU determines that the washing fluid pump is already off 614, the speed of the blood pump and the speed of the filtrate pump is increased 616 to the maximum pre-set limit in an effort to remove liquid from the reservoir 20 and thereby eliminate the overflow condition quickly.
  • FIG. 7 illustrates the pneumatically driven, multichannel clamp 50 used in the present invention.
  • Any pneumatic piston may be used in the invention, but a piston commercially known as a pancake piston may be particularly suitable.
  • the pancake piston 112, illustrated in FIG. 7, comprises a pneumatic piston 112, a piston shaft 114, a piston shaft rod 116 connected to the piston shaft 114, an occluder 115 attached to the piston shaft rod 116, an upper tubing guide 118 positioned parallel to the occluder 115 and a lower tubing guide 119 positioned parallel to the occluder 115.
  • the clamp 50 is structured to retain two tubes, namely blood line 104 and washing fluid line 106, between the upper tubing guide 118 and the occluder 115, and two tubes, namely blood line 96 and washing fluid line 48 between the occluder 115 and the lower tubing guide 119.
  • the piston 112 is attached to a flange 120 by means of two threaded bolts 122.
  • the upper tubing guide 118 and lower tubing guide 119 are also attached to the flange 120 by means of two threaded bolts 124.
  • the piston shaft rod 116 is attached coaxially to the piston shaft 114 through a threaded pin 117.
  • the occluder 115 is attached to the piston shaft rod 116, in perpendicular orientation thereto, and is movable therewith as the piston shaft rod 116 moves up and down with the piston shaft 114.
  • the piston 112 includes an internal chamber 125 having a port 126 through which high pressure air is applied to the chamber 125.
  • a barrier 127 slidably positioned within the chamber 125, is attached to the piston shaft 114 and is movable with the piston shaft 114.
  • a tension spring 113 is biased between the barrier 127 and the bottom of the chamber 125 and forces the barrier 127, and thus the piston shaft 114, upwardly under normal conditions (i.e. , when high pressure air is not supplied to the chamber 125).
  • the clamp 50 is, therefore, in a deactivated mode.
  • the upward force of the tension spring 113 on the piston shaft 114 and piston shaft rod 116 also forces the occluder 115 against the upper tubing guide 118 to compress tubing lines 104 and 106 positioned therebetween.
  • the occluder 115 is spaced from the lower tubing guide 119 and as a result, the tubing lines 48 and 96 remain open during deactivation of the clamp 50.
  • the blood salvaging apparatus is in the reverse filtration mode.
  • a vacuum system may be used to effect alternating compression of the tubing lines.
  • the vacuum may not provide adequate force required to occlude the tubings completely, especially when the fluid pressures in the tubings are high.
  • the reliability and simplicity of the system is improved by the use of the above described single clamp 50, instead of two or more clamps to switch from membrane filtration to reverse filtration.
  • FIG. 8 illustrates the relationship between the blood salvaging elements of the invention and the control unit CU.
  • the structural components of the blood salvaging apparatus shown in FIG. 8 are the same as those shown in FIG. 1A, except that these components are shown to be mounted on an instrument cabinet 800 consisting of a control unit CU front panel and an i.v. pole 802, but the individual elements are not shown to scale or in correct size relative to each other.
  • the control unit front panel shows knobs for setting standby time STANDBY T 804 (e.g. , one minute), reverse filtration time RF TIME (e.g. , one minute), maximum positive pressure PI MAX 808 (e.g. , 150 mm Hg), and maximum negative pressure P2 MAX 810 (e.g. , -50 mm Hg).
  • the control unit front panel also shows four dual set point relay meters which continuously display hematocrit values HCT-1 812 and HCT-2 814, blood pump speed
  • HCT-1 e.g., 0% to 11.7%
  • HCT-2 e.g. , 30% to 40%
  • blood pump speed e.g. , 100 ml/min to 500 ml/min
  • washing fluid pump speed e.g., 100 ml/min to 500 ml/min.
  • alarm indicators both audio and visual, for indicating high positive pressure PI in the blood line 56, high negative pressure P2 in the filtrate line 72, high hematocrit HCT-2 at the membrane filter outlet 90, the presence of air in the venous line 94, overflow in the cardiotomy reservoir 20, and visual indicators for different modes of operation (i.e. , filtration mode, standby mode, and reverse filtration mode).
  • the control unit displays and meters can be configured in many different ways by those skilled in the electrical arts.
  • the autologous blood salvaging system of the present invention provides distinct advantageous over prior blood recovery systems.
  • the blood salvaging system of the present invention may be used for humans as well as animals, with some minor variations.
  • reference herein to specific details of the illustrated embodiments is by way of example and not by way of limitation. It will be apparent to those skilled in the art that many modifications of the basic illustrated embodiment may be made without departing from the spirit and scope of the invention as recited by the claims.

Abstract

L'invention concerne un appareil de récupération de sang comprenant un dispositif d'aspiration (12), un dispositif de mélange (15, 20) destiné à mélanger le sang aspiré avec un fluide de lavage, un dispositif de filtrage (18) destiné à filtrer le mélange à travers un filtre à emboles, un dispositif de contrôle (32) destiné à mesurer le volume de composants cellulaires dans le sang aspiré et filtré, un dispositif de filtration (54) destiné à éliminer l'excès de fluide et les impuretés du sang et un dispositif de réinjection (94, 97, 102) destiné à réinjecter au patient le sang lavé et filtré, débarrassé de ses emboles. Ledit appareil est conçu pour introduire un fluide de lavage dans le sang aspiré proportionnellement au volume hématocrite mesuré pour le sang aspiré. L'invention concerne également des procédés destinés à amorcer le système, à nettoyer et purger l'appareil du sang coagulé et de débris par une filtration inversée, ainsi qu'à filtrer le sang pour une réinjection. L'invention concerne enfin des procédés de commande automatique du système et de l'opération de récupération de sang.
PCT/US1997/024126 1997-01-03 1997-12-31 Systeme peroperatoire de recuperation de sang et procede afferent WO1998029149A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US3399897P 1997-01-03 1997-01-03
US60/033,998 1997-01-03
US08/876,557 1997-06-16
US08/876,557 US5876611A (en) 1997-06-16 1997-06-16 Intraoperative blood salvaging system and method

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US8262552B2 (en) 2008-06-10 2012-09-11 Sorin Group Italia S.R.L. Securing mechanism, particularly for blood separation centrifuges and the like
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WO2016145198A1 (fr) * 2015-03-10 2016-09-15 Viatar LLC Systèmes, procédés et dispositifs pour éliminer des cellules tumorales en circulation du sang
CN107126584A (zh) * 2017-05-09 2017-09-05 中国人民解放军第二军医大学第二附属医院 清除引流液中血细胞并协助成分定量的负压过滤装置
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US10039876B2 (en) 2014-04-30 2018-08-07 Sorin Group Italia S.R.L. System for removing undesirable elements from blood using a first wash step and a second wash step
EP3563772A1 (fr) * 2012-08-14 2019-11-06 The General Hospital Corporation Appareil de collecte de tissus
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WO2020260836A1 (fr) 2019-06-27 2020-12-30 I-Sep Système et procédé de traitement de liquide hémorragique pour de l'autotransfusion
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US11534344B2 (en) 2013-02-20 2022-12-27 Cytrellis Biosystems, Inc. Methods and devices for skin tightening
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EP1254675A1 (fr) * 2001-04-30 2002-11-06 DIDECO S.p.A. Procédé et dispositif pour commander l'étape de rinçage dans une enceinte pour la centrifugation du sang
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US8506825B2 (en) 2006-11-27 2013-08-13 Sorin Group Italia S.R.L. Method and apparatus for controlling the flow rate of washing solution during the washing step in a blood centrifugation bowl
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US8485957B2 (en) 2008-06-10 2013-07-16 Sorin Group Italia S.R.L. Securing mechanism, particularly for blood separation centrifuges and the like
US9308314B2 (en) 2011-04-08 2016-04-12 Sorin Group Italia S.R.L. Disposable device for centrifugal blood separation
US11717317B2 (en) 2012-08-14 2023-08-08 The General Hospital Corporation Method and apparatus for tissue harvesting
EP3563772A1 (fr) * 2012-08-14 2019-11-06 The General Hospital Corporation Appareil de collecte de tissus
US11534344B2 (en) 2013-02-20 2022-12-27 Cytrellis Biosystems, Inc. Methods and devices for skin tightening
US10293098B2 (en) 2014-04-30 2019-05-21 Sorin Group Italia S.R.L. System for removing undesirable elements from blood using a first wash step and a second wash step
US10039876B2 (en) 2014-04-30 2018-08-07 Sorin Group Italia S.R.L. System for removing undesirable elements from blood using a first wash step and a second wash step
CN104014006A (zh) * 2014-06-17 2014-09-03 伍锟 一种应用于手术中出血病人的同步血液回输系统
US11896261B2 (en) 2014-11-14 2024-02-13 Cytrellis Biosystems, Inc. Devices and methods for ablation of the skin
US10702647B2 (en) 2015-03-10 2020-07-07 Viatar LLC Systems, methods, and devices for removing circulating tumor cells from blood
US11607480B2 (en) 2015-03-10 2023-03-21 Onco Filtration, Inc. Systems, methods, and devices for removing circulating tumor cells from blood
WO2016145198A1 (fr) * 2015-03-10 2016-09-15 Viatar LLC Systèmes, procédés et dispositifs pour éliminer des cellules tumorales en circulation du sang
US11464954B2 (en) 2016-09-21 2022-10-11 Cytrellis Biosystems, Inc. Devices and methods for cosmetic skin resurfacing
CN107126584A (zh) * 2017-05-09 2017-09-05 中国人民解放军第二军医大学第二附属医院 清除引流液中血细胞并协助成分定量的负压过滤装置
CN107126584B (zh) * 2017-05-09 2023-08-25 中国人民解放军第二军医大学第二附属医院 清除引流液中血细胞并协助成分定量的负压过滤装置
CN111989126A (zh) * 2017-12-28 2020-11-24 艾赛普公司 用于处理出血流体以便自体输注的系统和方法
US11583615B2 (en) 2017-12-28 2023-02-21 I-Sep System and method for treating haemorrhagic fluid for autotransfusion
US11607478B2 (en) 2017-12-28 2023-03-21 I-Sep System and method for treating haemorrhagic fluid for autotransfusion
CN108106922A (zh) * 2018-01-31 2018-06-01 迈克医疗电子有限公司 一种浓缩混匀机构
CN112135648A (zh) * 2018-05-17 2020-12-25 甘布罗伦迪亚股份公司 具有气体分离装置液位控制的处理设备和方法
CN114286695A (zh) * 2019-06-27 2022-04-05 艾赛普公司 用于处理出血性流体以进行自体输血的系统和方法
FR3097770A1 (fr) * 2019-06-27 2021-01-01 I-Sep Système et procédé de traitement de liquide hémorragique pour de l’autotransfusion
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